Is a plot twist kind of like the climax?

It can be part of the climax, but is not defined as the climax. The plot twist is the part of the story that reveals something surprising/unexpected (e.g. when the tables are turned on a character or the killer is revealed to be someone thought to have been a good guy or was dead)

I guess it could be but there's too many plot twists in many movies. There would be too many climaxes

A plot twist is when the plot of the movie suddenly takes a turn that the audience didn't expect. It's not necessarily the climax, although it can be. A plot twist usually serves to advance the story towards the climax.

It can be,
there are story arcs within story arcs and climaxes within those arcs. So it may not be the main climax but definitely an important one. A plot twist can happen at the climax and usually does. But it isnt the same thing in my understanding

No, the climax is the final dramatic scene. A plot twist can happen anytime.

Not always....you can have many plot twist but almost always 1 climax...you can have mini climax to build up the story